The Disaster Research Center (DRC) at The Ohio State University proposes to conduct a systematic and comparative study of the delivery of emergency medical services (EMS) in large-scale and relatively sudden disasters in the United States. The objectives of the research are to establish the nature and parameters of the conditions for, characteristics of, and consequences from the efforts to provide EMS in turbulent social environments such as catastrophes and collective crisis situations. Building on some earlier DRC exploratory work, an effort will be made to answer the following questions: (1) What are the pre- and trans-disaster circumstances and factors that affect the nature and pattern of disaster-related EMS? (2) What are the characteristics of the EMS delivered in disasters, i.e., by whom, what, for whom, how, why and where are EMS provided by the health care delivery system in major disasters? and (3) What are some of the more important differential effects, internal to the health care delivery system, resulting from the delivery of EMS in disasters? Focusing primarily on organizations as the subunits within the systems to be analyzed, it is anticipated we will examine through in- depth interviewing, participant observations and document gathering, several dozen medical care systems providing EMS in extreme stress situations. This intensive and extensive field work on community health care delivery systems faced with circumstances maximizing problems and requiring quick adaptability would be the first ever of its kind. The empirically-based findings should have important implications for general EMS training and education, and will suggest guidelines for the planning of the organization and delivery of disaster-related EMS.